ns4.inwx.com has no MX records.
Question and response
Question
dig ns4.inwx.com. MX
Answer
The response has no answer records.
Authority
inwx.com. 1800 SOA damon.ns.cloudflare.com. dns.cloudflare.com. 2397278544 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0